Severe UI lag and React rendering issues even for medium-sized repos (few hundred files)

### 🐛 Bug: Severe performance issues even with medium-sized repositories

**Describe the bug**
GitVizz becomes noticeably slow and laggy even when visualizing repositories with a *few hundred files*. This is not an extreme edge case — for example, the GrapesJS repository triggers significant UI lag during rendering and interaction.

This suggests React component rendering or layout computation is breaking down much earlier than expected.

---

### 📌 Steps to Reproduce

1. Open https://gitvizz.com
2. Use the **GrapesJS** repository (≈ a few hundred files).
3. Wait for the visualization to load.
4. Interact with the UI:
- Expand folder trees
- Navigate between components / graphs

---

### ⚠️ Observed Behavior

- UI stutters and freezes during interaction.
- Delays when expanding folders or navigating views.
- High CPU usage during renders.
- Feels unresponsive even on modern hardware.

---

### 🧪 Expected Behavior

- Smooth interaction for repositories with a few hundred files.
- React components should remain responsive at this scale.
- Minimal blocking of the main thread.

---

### 🖥️ Environment

| Item | Details |
|-----|--------|
| Device | Mac Mini M4 |
| Browser | Safari (latest) |
| Repo Size | Few hundred files |
| Example Repo | GrapesJS |